black ls-14

Hey everyone. I have recently acquired an 88 Rx-7 GTU. The guy I got the car from used it as a daily driver. He put 115,xxx miles on it. He recently tried to install a stereo, but he did so without buyin the neccesary harnesses. He just cut and spliced the wires from the factory unit. After he was finished, the car would not crank. He gave the car away because his mechanic said it was gonna cost nearly $1000 to fix. This is what i understood anyway as the guy didnt speake no english. Anyway, i messed around with it a little and this is what I have come up with. Everything electrical not related to the engine works fine. Lights, dash, sunroof, a/c system. The engine cranks over fine, however there is no spark, and no fuel. The fuel pump is not working and there is no signal going to the injectors. At first i thought it was the ECU, so i changed that out, but it made no change. Has anyone else run across this same thing. If not, what are some other things i need to check for? Any help would be greatly appreciated.

Aaron Cake

iTrader: (1)

Who knows what he cut...

Check the basics first. Verify that all the fuses work. It might be as simple as a blown EGI fuse. Check to make sure the main relay is getting a 12V IGN signal. Maybe he cut that line from the key switch for the stereo installation?

black ls-14

I've checked the main fuse block and all fuses under the hood. They are all good as are the fuses under the dash. Where is this relay located that I need to check?

bluspd

iTrader: (1)

can this car really not be running just because someone tried to install a stereo?...im helping ls w this project btw...we also tried another ecu and still nothing, engine turns over but wont start, still no fuel or spark...CALLING ALL ROTORY GURUS...help

...i forgot to mention that i can hear thing clicking under the hood when the key is turned on but im not sure if the main relay is working or not...where is this "main relay?"

black ls-14

I have a lead on what the problem might be, but I need some info if anyone out there can help me. On the power lead going to the main relay. Is there anyone out there that can tell me what amount of resistance (in ohms i guess) I should have from that lead to say the battery terminals or somthing. What I am trying to figure out is why we dont have any voltage going to the relay. Its kinda weird. Right now we have just under 3 volts getting to the relay. When I wire 12 volts from the battery directly to the relay, then we only have 5 volts getting to the fuel pump, which we had 0 volts before the hotwire. I think we have a broken wire somewhere, but i can tell if it is in the power wire or the ground. Also, what is the minimum voltage in which the coil can emit a spark. Im a total wiring noob so any help is greatly appreciated. THanks guys.

Aaron Cake

iTrader: (1)

OK, grab yourself a Haynes manual and/or download the wiring diagrams from the FSM in the FAQ. You will absolutely need these diagrams to troubleshoot the car. From what I remember, the main relay is a straight shot from the IGN switch. But verify this first, as I don't have the diagrams handy at the moment.

black ls-14

Ok. We have been tryin to figure out this wiring problem. We fixed most of the wiring. We also found the 15A Engine fuse under the dash to be blown. The moment we inserted a new fuse, it popped. So just to see if what we had previously done worked we installed a 30A. Now we have fuel and spark, but the wires going into the fuse box started gettting hot. My question is what exactly is this fuse for. What i mean is what comes off of this fuse that we can check for a short circuit. I bought a Haynes manual and looked at the wiring diagrams, but bein the noob i am, they dont make any sence to me.

black ls-14

OK. another update. We found where our short to ground is. It is grounding through the ILLUM wire. So we pulled that fuse hoping to stop the short, but the short is on the ground side of that wire. So what I need to know is where the ILLLUM wire is routed out of the fuse block. Im hoping we can follow that to wherever the short circuit is. Any help would be greatly appreciated.

Aaron Cake

iTrader: (1)

The illumination wire runs all around the underside of the dash. Since the stereo harness was hacked, make sure that wire was not cut off in tha area and grounded.

bluspd

iTrader: (1)

im workin on this car also and i was wonderin what circuits ran off the engine fuse. the engine fuse is the one immediately blowing when the key is turned on but the illumination wire is the one that got hot when we put a 30 amp fuse in the engine fuse spot...im guessing the illumination circuit is backfeeding through the engine circuit or vice versa....we just need to know where these circuits might intersect so we can track down this short, thanks